Presently, certain of the more expensive makes of automobiles are being sold with intermittent braking provisions, but, these are electrically controlled haudraulic braking systems. In general, heavier vehicles such as trucks and the larger or heavy-duty pickups using the computer controlled intermittent air brakes requiring complex independent control of the application and release of brake shoes at each wheel are not economically successful. However, my U.S. Pat. No. 4,538,859 issued Sept. 3, 1985, is an On/Off Air Braking System which interrupts the trucks main high pressure line under electrical valving control and thereby avoids the complexities of independent wheel monitoring.